This invention relates to the art of cartons or containers commonly constructed of a corrugated paperboard suitable for produce and the like. More particularly, the invention is concerned with a rigidly interlocking bottom closure for a carton.
Corrugated paperboard cartons having a wide variety of constructions are well known in the art. Many of these carton designs employ a plurality of overlapping closure flaps which interlock in various fashions to securely close the top of the carton and a plurality of overlapping bottom closure flaps interlocked to securely close the bottom of the carton. In constructing cartons or containers for fresh fruits and vegetables, it is especially important to provide a strong bottom closure arrangement capable of supporting the considerable weight of the contents.
Frequently the carton manufacturer is located far from where the commodities are to be packed. Thus, as a practical matter, the carton must be capable of being shipped in a flat, collapsed configuration to use shipping and storage space efficiently. Once at the packing location, the flat, collapsed carton must be constructed to be easily fully assembled without requiring skilled personnel or complex equipment. Thus, the action necessary to convert the flat carton from its collapsed condition to its fully assembled state should be performable quickly and simply, preferably without the need to utilize glue, staples or other equipment to secure the carton closure flaps.
For many years, the corrugated paperboard industry has needed a produce box that has a fast locking bottom capable of holding heavy loads such as potatoes, squash, cucumbers, etc. While numerous designs have been tried, these have generally failed in attempting to accommodate heavier loads.
Some bottom closure attempts have adopted the use of a solid blank bottom but this requires a large amount of corrugated paperboard in the manufacture and thus is economically too costly. Another previous approach to enable handing heavy product loads and still have an economical carton was to require the bottom to be glued or stitched. This type carton has not been used as a practical matter because the produce man or farmer did not want to take stitching equipment into the field with him. Also he did not want to have to stitch up the carton bottoms in advance because these "made-up" cartons required to much room for storage and/or transport to the field location where the produce is being harvested.